1. Technical Field
This invention relates in general to the controlling electromagnetic emissions and in particular to a device and method for grounding high speed circuit electromagnetic emissions.
2. Background Art
The ever-increasing speed of modern computer processors or CPUs has given rise to increased electromagnetic interference (EMI) emissions. As a result, the need to develop better techniques and procedures for controlling EMI has also increased to keep pace with U.S. and European emission regulations.
In the prior art, high speed circuit electromagnetic emissions are typically eliminated or reduced via a direct ground connection which allows a return path for the high speed signals. The return paths are generally located close to the point of origin to reduce the length of the return paths and reduce the amount of radiating area that can 15 release the emissions. The suppression of radiating signals can be accomplished through spring clips or conductive gaskets from the source to ground. As long as the processors remained close to the electrical or motherboard they were attached to, EMI reductions involving spring clips were not needed.
However, with the advent of new, ultra high speed slot-type processors, improved EMI reduction techniques are needed. Slot-type processors are pluggable in a vertical orientation with resect to the system motherboard, and are currently capable of speeds in the range of 300 to 750 MHZ. This problem is further compounded by the fact that the heatsinks used to cool the processors are the primary source of the CPU's radiated energy and emissions. Since the heatsinks are typically free-floating (i.e. not attached to the system planar board), the emissions are free to radiate throughout the system and out of the system enclosure.